Merge "Fix NPE crash when start pending predictive back animation." into main

        // Ensure the final animation targets which hidden by transition could be visible.

        for (int i = 0; i < targets.size(); i++) {

            final WindowContainer wc = targets.get(i).mContainer;

            if (wc.mSurfaceControl != null) {

                wc.prepareSurfaces();

            }

        }

        // The pending builder could be cleared due to prepareSurfaces

        // => updateNonSystemOverlayWindowsVisibilityIfNeeded